Vacuum breaker for valve stem packing



FIG. 1 is a top plan view of a vacuum breaker for valve stem packing showing our new design;

FIG. 2 is a bottom plan view thereof;

FIG. 3 is a perspective cross sectional view taken on line 3--3 of FIG. 1; and

FIG. 4 is an exploded perspective view thereof. 

The ornamental design for a "vacuum breaker for valve stem packing," as shown. 